An aortic aneurysm is a very common deteriorating disease typically manifested by a weakening and expansion of the aorta vessel wall. Aneurysms affect the ability of the vessel lumen to conduct fluids, and may at times be life threatening when, for example, rupture of the vessel wall occurs. A standard treatment for repairing an aneurysm is to surgically remove part or all of the aneurysm and implant a replacement prosthetic section into the vessel. Such surgery, however, is generally postponed until the aneurysm has grown to a diameter greater than five centimeters. With aneurysms over five centimeters in diameter, the risk of complications is greater than the risks inherent in surgical incision and grafting of the aneurysm. Consequently, aortic aneurysms measuring greater than five centimeters in diameter, and those showing rapid increase in size, are generally surgically engrafted as a matter of course, before rupture occurs.
The standard procedure for repairing an aortic aneurysm requires one or two days of preparing the large and small intestines prior to hospitalization. The operation itself generally takes one to three hours to perform, and necessitates several units of blood for transfusion. The patient commonly remains hospitalized for several days following surgery, and requires as much as three months recuperation time before returning to work.
Moreover, there remains a significantly high rate of mortality and morbidity associated with the standard procedure. The mortality rate is as high as eight percent, while the morbidity rate includes incident complications such as blood loss, respiratory tract infections, wound infections, graft infections, renal failure, and ischemia of the bleeding intestine. The typical aortic aneurysm patient is also elderly and, therefore, less able to withstand major surgery, including anesthesia; this further influences the morbidity and mortality rates.
The repair of aneurysms located in the aortic arch or in the thoracoabdominal region introduce additional complications because of their location and the curvature of the vessels, especially around the aortic arch. Accordingly, the existing surgical techniques for repairing aneurysms in these areas are also associated with significant mortality and morbidity.
Non-surgical treatments for repairing an aneurysm include deploying a graft device at the aneurysm site via a catheter traveling through the femoral artery. Conventional tubular aortic replacement sections, however, are generally considerably larger in diameter than the femoral artery and, therefore, cannot be inserted through the femoral artery lumen to the site of the aneurysm.
Even in the more advanced aortic graft assemblies which enable percutaneous deployment and placement of a spring loaded graft for a non-surgical correction of an aortic aneurysm, the required entry profiles require at least 10-12 FR. This is the case because these graft systems are comprised of graft material, two or more spring stents, a balloon catheter, a sheath introducer, and plunger at a minimum, for deployment of the graft.
Consequently, there have been efforts to design smaller devices for the non-surgical techniques to facilitate percutaneous entry and movement of the graft assembly through the arteries. Another important factor is the ability of the interventionist to control the graft assembly during the procedure. If the graft assembly is not deployed correctly, it may not make a proper seal, other problems may occur and the procedure may have to be repeated. Thus, reducing the size of the graft assembly and improving control over the graft assembly during deployment are both important factors for improving the non-surgical procedures.
For the thoraco and thoracoabdominal arterial trees, the curvature and shape of the arteries create a heightened need for control over deployment and positioning of the grafts.
Accordingly, what is needed is an improved apparatus and method for percutaneous deployment and placement of a graft in the thoracic and thoracoabdominal arterial tree.